Making a leaking water heater safe
- Close the cold inlet.Find the valve on the cold supply line at the top of the heater and turn it off. This stops new water entering the tank.
- Turn off the heat source.On a gas heater, turn the gas control knob to off or pilot. On an electric heater, switch off its breaker. Do this from a dry spot.
- Close the main if water keeps coming.If the leak is on the supply side before the inlet valve, or the inlet valve fails, close the main shutoff.
- Let the water cool.Water in the tank can be scalding. Do not open the drain valve or loosen fittings until it has cooled.
- Find where it is coming from.Dry the area and watch the connectors, the relief valve and its discharge pipe, the drain valve and the bottom of the tank.
Where the water is coming from
| Source | What it usually means | Typical outcome |
|---|---|---|
| Flex connector at top | A worn or corroded connector or loose fitting | Repair: replace the connector |
| Temperature and pressure relief valve | Valve opening due to high pressure or temperature, or a worn valve | Diagnose the cause; possibly replace the valve and check pressure |
| Drain valve at bottom | Worn or partly open drain valve | Repair: tighten or replace the valve |
| Bottom or seams of the tank | The tank has corroded through | Replacement is usually the only fix |
| Floor drain pan full | Could be any of the above or condensation | Trace the source before deciding |
Hard water and tank life
Fullerton's hard water leaves sediment in the bottom of tank heaters. Sediment can make a heater rumble, reduce efficiency and contribute to corrosion of the tank over time. A tank that leaks from its body cannot be patched; at that point the conversation is about replacement.
Any heater work in California should leave the heater seismically strapped. If the old heater was moved or shaken loose during the leak, check that the straps are secure.
Repair or replace?
- IfThe leak is at a connector, nut or drain valveThenThis is normally a repair; the tank itself is fine.
- IfThe relief valve is dischargingThenAsk the plumber to check house pressure and the expansion tank before swapping the valve.
- IfWater is seeping from the tank body or bottom seamThenPlan a replacement; ask whether it needs a permit, which water heater replacements typically do.
- IfYou cannot tell where it is coming fromThenKeep the inlet closed and the heat off until a plumber traces it.
Common questions
Can I keep using hot water with a small leak?
Not safely until you know where it is coming from. A failing tank can let go suddenly, and a relief valve that discharges may be signaling a pressure problem.
Is a dripping relief valve normal?
Occasional small discharge can happen with thermal expansion, but repeated dripping should be checked. Never cap or plug the relief valve or its discharge pipe.
Does a new water heater need strapping?
Yes. Water heaters in California must be seismically strapped. A plumber replacing one should strap it and can tell you about permit requirements.
General information for Fullerton, not a quote or professional advice. In an emergency, call 911.